pp. 212-233.
Biotechnology Letters, Vol. 27, No. 18. (September 2005), pp. 1337-1347.
Applied Animal Behaviour Science, Vol. 100, No. 1-2. (October 2006), pp. 103-116.
Journal of Evolutionary Biology, Vol. 18, No. 2. (March 2005), pp. 464-473.
Nature, Vol. 447, No. 7144. (30 May 2007), pp. 539-540.
Nature, Vol. 447, No. 7144. (31 May 2007), pp. 581-584.
Behavioral Ecology and Sociobiology, Vol. 13, No. 3. (1983), pp. 229-238.
Biological Reviews, Vol. 73, No. 4. (1998), pp. 413-448.
Journal of Ornithology, Vol. 147, No. 3. (6 July 2006), pp. 504-506.
Ibis, Vol. 144, No. 2. (2002), pp. E67-E72.
Behavioral Ecology and Sociobiology, Vol. 34, No. 2. (1 February 1994), pp. 113-123.
Biological Reviews, Vol. 73, No. 3. (1998), pp. 267-292.